Discovery and analysis of Staphylococcus aureus biofilm inhibitors using functional metagenomics approach / 生物工程学报

Although most microbes are not readily cultured in the lab, microbial DNA can be extracted directly from an environmental sample and be functionally expressed in a suitable host for natural products discovery, and this approach has been termed "metagenomics". An E'mei Mountain soil metagenomic library was constructed using an Escherichia coli-Streptomyces shuttle vector for functional based screening of anti-bacterial clones in Streptomyces albus host. Two active clones were obtained and their fermentation broths were studied for the inhibitory effect on Staphylococcus aureus biofilm. Their fermentation products have a good inhibitory effect on the formation of S. aureus biofilm, and the inhibitory effect could exceed 90% when the concentration of sample was 2 MIC (Minimum Inhibitory Concentration). In addition, two samples had significantly effect on S. aureus biofilm dispersal, and the clearance rate of EM110 was higher than EM123. In conclusion, substances with strong bioactivities on biofilm formation and dispersal of S. aureus could be discovered by using metagenomics technology.

Optimization of Ethanol Mixed-extraction Technology of Red ginseng and Salvia miltiorrhiza in Xinlikang Granules by Multiple Indexes Comprehensive Evaluation Method Combined with Orthogonal Test / 中国药房

OBJECTIVE:To optimize the ethanol mixed-extraction technology of Red ginseng and Salvia miltiorrhiza in Xin-likang granules. METHODS:L9(34)orthogonal test was adopted to optimize ethanol mixed-extraction technology with ethanol vol-ume fraction,amount of ethanol and extraction times as factors using weighting coefficient comprehensive score of the contents of ginsenoside Rg1,Re and Rb1 in R. ginseng and the contents of tanshinone ⅡA and salvianolic acid B in S. miltiorrhiza as index;and the verification test was detected. RESULTS:Optimal mixed-ethanol extraction technology was as follows as 6-fold 70% etha-nol,reflux extracting for 3 times,2 h each time. In verification test,average contents of ginsenosides Rg1,Re,Rb1 in R. ginseng and those of tanshinone ⅡA and salvianolic acid B in S. miltiorrhiza were 3.963 8,0.757 3,4.986 2,0.964 7,27.662 5 mg/g,re-spectively,and comprehensive score was 0.96 (RSD=1.26%,n=3). CONCLUSIONS:Ethanol extraction technology of R. gin-seng and S. miltiorrhiza in Xinlikang granules optimized by multiple indexes comprehensive score combined with orthogonal test is stable,reasonable and feasible.